1. Field of the Invention
The present invention relates to an arrangement for the electromechanical measurement of the axial clearance of rotating components and, more particularly, the measurement of the axial clearance of shafts in high-speed turbomachinery, including a housing which can be fixed relative to a measured object. A motor-driven rotatable member is supported within the housing, with which a sensor is movable towards the measured object and, after the triggering of a contact impulse, is moved away from the measured object. The sensor is electrically insulated from the housing and from the measured object.
2. Discussion of the Prior Art
An arrangement has become known from the periodical "Records for Technical Measurement", issue of January 1974, pages 11 and 12, which is adapted for the measurement of distances, in effect more precisely, for the measurement of the radial gap between compressor or turbine blade tips and the inner wall of the housing adjacent the blade ends.
For this purpose, in the known arrangement the result of the measurement is adapted to be determined by the displacement of an axially movable sensor pin through the intermediary of a differential transformer linear transducer, which is arranged at both sides of a pin-like extension of the sensor opposite the location of measurement. The utilization of this apparatus for axial clearance measurement by means of an eccentric feeler is not possible, inasmuch as the sensor pin only moves in an axial sliding movement.
Moreover, temperature-occasioned uncontrolled thermal expansions of the pin-like extension lead to errors in measurement in the above case, and namely in particular, when this extension must be constructed relatively lengthy for reasons of installation.
Consequently, the above-mentioned known arrangement is very largely unsuitable for axial clearance measurement, especially when the constructional demands of the machine involved, for instance, a gas turbine jet engine, facilitate only a lateral accessibility to the measured object, meaning in a radial direction to the rotor, whose axial clearance is to be measured.
Contemplated in particular hereby is the rotor of the gas generator of a gas turbine jet engine constructed with a plurality of shafts wherein, for example, the high-pressure turbine of the gas generator has connected thereto at least one further turbine for the drive of a low-pressure or intermediate-pressure compressor arranged ahead of the high-pressure compressor.